Supply of fuel to internal-combustion engines



J. W. BOND] April 13, 1954 SUPPLY OF FUEL. TO INTERNAL-COMBUSTION ENGINES 2 Sheets-Sheet 1 Filed June 8. 1950 2 ii; i, Q, iclclclFFlc 3 2 3 m l\ 7 3 a m43 M 6 2 L 7 7 2 a 2m \l|ll|| L 5 1 G \l l|.| m l l r F 1 G M 7 F g April 13, 1954 w. BOND! 2,574,984

SUPPLY OF FUEL TO INTERNAL-COMBUSTION ENGINES Filed June 8, 1950 2 Sheets-Sheet 2 UNITED STATES PATENT OFFICE SUPPLY OF FUEL TO INTERNAL- COMBUSTION ENGINES Joseph Werner Bondi, Wotton-under-Edge, England, assignor to Associated British Oil Engines Limited, Lougliborough, England,

company a British Application June 8, 1950, Serial No. 166,928

Claims priority, application Great Britain J une 8, 1949 1 Claim. (Cl. 12332) of fuel, it is convenient to visualise the enclosed i' space as divided into a number of volumes, which may be termed prismatic volumes, extending parallel to the axis of the cylinder, for example, one such volume having as end surfaces the mouth of said recess and a like transverse area on the opposite element, and one other such volume having as its end surfaces the remainder of the recessed element and the opposite part-surface of the co-operating element. In order to achieve the desired compression ratio, the end surfaces defining said latter volume may be brought very closely together when the piston attains its outer dead centre. It will be appreciated that such end surfaces need not be right transverse planes, but may be oblique and/or curved.

In such a combustion chamber, during the approach of the piston to its outer dead centre, the rate or degree of reduction of volume is not uniform throughout the enclosed space, that is, as between the aforesaid prismatic volumes, which have different axial dimensions; the volume whose end surface includes the said recess has the greater axial dimension, and undergoes a lower rate of reduction than the volume whose end surfaces are constituted by closely approaching surfaces of the piston crown and cylinder head. This dilference of rates of volume reduction imparts an internal displacement to the air charge, which is known and will hereinafter be referred to as an air squish effect.

In compression-ignition engines, including those of the kind described, it has hitherto been common practice to inject the fuel into the combustion chamber and to atomise it with the aid of a fuel pump and an atomising injector which apply very high pressure to the fuel.

The present invention has for an object to eliminate the use of high pressure or jerk" pumps and high pressure injectors which, being usually required to supply and atomise small quantities of fuel at each operation, necessarily comprise small parts that have to be made of very high grade materials and by very accurate machining in order durably to withstand and effectively to operate under the high pressure.

Accordingly, the invention provides, in an en gine of the kind described, means for atomising by said air squish effect fuel introduced at a controlled rate with the aid of a metering device.

More particularly, fuel atomising means in an engine of the kind described may comprise an obturator body disposed within the combustion chamber so as to enter and substantially enclose said recess on the approach of the piston crown element to the cylinder head element, and thereby to divide the combustion chamber into two volumes one of which comprises the recess and is subject to a lower rate of volume reduction than the other volume, at least one passage for air under displacement to said one volume from said other volume, a receiving chamber for fuel in the cylinder head, a feed duct to the receiving chamber, a non-return valve associated with the feed duct and at least one atomising duct extending from the receiving chamber to convey fuel from said chamber to the recess under the air displacement.

The invention may further provide, for mounting in the cylinder head of an engine having a piston with a recess in its crown, an obturator body in which are formed the aforesaid receiv ing chamber, feed duct, atomising duct and air passage.

Alternatively an obturator body may be integral with or mounted on the piston, and the recess may then be located in the cylinder head.

An obturator body mounted in the cylinder head may have extending through an aperture in its inner end a jet member, the peripheral wall of which has a plurality of grooves or fiutes to constitute with the surrounding wall of the aperture a plurality of atomising ducts. Such a jet member may have a stem displaceable axially in the obturator body and incorporating the non return valve.

The or each passage for air under displacement may extend from the combustion chamber into the fuel receiving chamber for ejecting the fuel in the latter chamber by pressure.

In an alternative arrangement, the or each I passage for air under displacement may extend transversely across that end of an atomising bore which is remote from the receiving chamber, for inducing fuel from the latter chamber. Such passage may extend through the obturator body or alternatively may be constituted by annular clearance between the peripheral walls of the obturator body and the recess. The or each of such passages may have a Venturi section, the atomising bore opening into its narrowest portion.

In any of the aforesaid variants of the obturator body, said body may be adjustable axially with respect to the element in which it is secured.

The fuel metering means for controlling the rate of fuel supply to atomising means as aforesaid may consist in a low pressure pump with positive d pla ement and capable of speed variation for controlling thquantitydlivered.

Alternatively, in atomising means wherein the air under displacement acts on the fuel by induc tion, the fuel metering device may comprise a valve, for example a screw down needle valve, in combination with the feed 'ductf'which valve serves to throttle and thereby control 'the'amount of fuel injected, since suchful extends-as an unbroken body or column through the obturator and induction of a quantity ofiuel from the receiving chamber into the aforesaid recess results under the automatic operationtif thnon retiijhi valve in its replacement by further fuel at a rate controlled by the setting of the meterir'ig valve. Some embodiments of the invention will be de cr bed. by war of. example with reference to he eqccm any e. dia rammatic drawin s where n; Q 1 an. enlar ed scale,

Figure 1 shows in axial section one embodiment. if htutat r hesiy mgunted in a cyl nd r 9a... qr castration rzithfa ece s in thepisto own E hts su rs n section. n. al ernative qbil ittq i my,

F 8 3, .139%. n. axia sec n yet another obturatorbbdy Figure 4 s in. axial e tion a. still. furthe ssum .Q hturator'hodymounted ina ylinder head. f

he nistq QEOWII, and;

.. me tarusect onal v ew show n Qtt einrention nclud n a fu The Pisto crown is. formed t llto which ahob urator bodys slams ts. w ll. be. s i d in det ilh rcln .tereincl uump P supplies. fuel to a fuel passage in the obturator body through ndu wh ch a ds onduit m ben 3a n. hich. a hrade n edle va ve. b. mounted r. hr ttl n he. hisv n ec ed by the fuel mm P- R ferrins efiisute i the. i ton I isshown W t ablll el s' l harmean f set. Cy n'r d galfopehipg. 9.315% qmhus ion chain-v er srl nden e d 2 has an obt ra or body 3 securedin an opening 13in co-axialrelao shil o openin he. 01Y. a that ore on tituting the. feed 'duct l which at its outer endhas anened. qr ien. fitqg ccommo atea c m r na il shrine lflq q t a nonr tumvalve 2 I, the. tern .0; whi h xte ds h us fi duct 4 and is surrounded at its outerend by the, spring 20; which is compressed betvi een a shoulder 2.2;,at theinner endlof the'l opening is anda nut 23. screwed on the outerend of the stem 24.

The non 'r'eturn valve 2| islocatedina fuel re-, ceivi'rig chamberi'fi at the innerv end of the body a; Radial passages 1 extend .T' from the chamber 6 so that their'ouiier endsopenjinto the cornbusr.

tion' chamber 11 adjacent the innrfsurface" of the'cylinder head 2, The inner en'd' ofthe chamber '6 has'ianaperture "21 which is closed by a valve '28 underthea'ction round the Valve stem '30 within the chamber 6, In the operaticn of this embodiment of fuel atomising means," during the piston Ifthe upper edge IS in the piston crown: passes of the obturator 3. A pressure setup, due to .thelower rate'of.volume"'reduction at the zone of theopening lain the piston t nt s. i t n crown.

f p' ns 9. su

upward movement of I l of the aperture the lower edge I2 difference is then.

' merits.

relative to the rate of volume reduction between the piston crown'and the surface of the cylinder head surrounding the body 3. This pressure difference ereates an air squish effect which forces air through the passages 1 into the chamber 6 and thereby cause the valve 28 to open to an extent suiii cient to afiord a conical atomising duct between theiace of the valve 28 and its seat, throughwh'ich fuel in the chamber 6 is expelled in atdmisd form into the recess I 5. Combustion of the fuel is therefore initiated within the recess I 5; and extends over the entire volume of thebofnbustidn'chamber I! as soon as downward movement of the piston causes the edge ll of aperture 16 to be withdrawn beyond the edge 12 of the body 3.

On. the attainm nt of, s tably reducedv p e sure within the chamber 6, at a subsequent stage of theengine cycle, the said chamber is refilled With fuel by means of a low pressure metering um not shown then nrr urn a v 2| open.- ing to permit the ingressoi further fuel and then cl g n er t actio of t e prin 26;-

In a te at ve embodime t f. obturator od 3. s own n s-igu e th eisp vide i a co-axial jet member 3 I the peripheral surface of which is formed with a pluralityof grooves or fl s. 3.2- Th s..:i t member s lo ted centn llr in v ertur 5. t he. nner end of thebodl 3, said aperture extending. froman annular fuel r c i h m er 3. ..W t wh ch adial passage mm n ca e ietmember fiiis mounted on a stem 3 5 and an inner irusto conical sur-. face 35 on said member serves in co-operation with aseat3'? asthe non-return valve. Thejet, member is urged upwardly. for the closing of the valve 36 byspring 20, housed in an enlarged part, is at theouterend of. the feedi'iuet i. and abut: ting a shoulder 22 atthe lower end of said enlarged part and. a collaror nut 23 secured tothe outer end oi the stem 35..

The operation of this embodiment is similar in principle to that of the preceding embocli- Air. underdisplacement from the vol-. ume between; the piston crown and the inner surface of thecylinder head. isforced radially in.- wards through the passages land expels, fuel from the receiving chamber 35* through the groovesor flutes}?! of the jet member 3: into the. recess such as .15 (Figure 1), these grooves; or flutes cooperating with the, surrounding .wall' of the aperture .33 i to constitute .atomising ducts, Again at a suitable stage in theenginecycle, reduction of pressure in chamber 34..permits.a low pressur metering pump todisplace thejet member 3|, and open the non-return valve 35. against the action ofspring 2b to conveys. fresh. fuel cha o hechamber. 34.

In theembodi ment shown in Figure 3 the n'lOdir, fiedobturator body, has. a. receiving. chamber v6, in. whichis located a. non-return valve..2.i: nor. mallymaintained inclosed position by a. spring; 20. From the, chamber Batomisingducts 9.ex-. tend, downwardly and outwardly eachto open intothe .narrowest por.tion of one ofa plurality of downwardlyv andinwardlydirected, Venturi-. shaped pa.ssages.3.8.1 which extend each fromone of the radialopeningsflin the body .i-to a central: apertureflsat the. innerend of said bod-y.v

In the operationof this embodiment, airiunder displacement from betweentthe piston crown and the inner surface of. the. cylinder head is forced: radially inwards. through the. openings? and the passages38; By. reason .of the form of these-pas-f sages, the air therein acquires where. it traverses the ends of the bores El a high velocity sufficient to induce fuel through these bores from the receiving chamber ii. Such induced fuel is then expelled in atomised form with the air through the aperture into a recess such as it (Figure 1) within the piston.

Further, in this arrangement since fuel is displaced from the chamber t by the inductive effect of air traversing the passages 38, the nonreturn valve 2i opens automatically on such withdrawal to replenish the chamber 3. The rate of supply of fuel to the feed duct s can therefore be controlled by a simple needle valve serving as the fuel metering device, since at all times an unbroken body or column or fuel must extend from the bores 9 through chamber 3 and feed duct 4 to the valve which is located in a fuel sup ply line connected to the duct i.

In the embodiment shown in Figure 4, air un der displacement from combustion chamber ll to the recess ill in the piston l is confined to an annular passage as between the peripheral surface ii of cbturator body it and the surrounding wall of the aperture from the recess [5 to the piston crown surface. In this ernbodiment the receiving chamber 5 communicates by way of radial passages til with a plurality of atomising bores as downwardly and outwardly directed to the peripheral surface t! of the body 3 so that on the approach of the piston crown to the inner surface of the cylinder head they are masked as shown by the wall of the aperture 56 in the piston crown. Thus air under displacement from the combustion chamber ['1 to the recess is forced at high velocity through the annular passage All and exercises an inductive effect through the bores 42 and passages as upon fuel in the receiving chamber 6. This fuel is thus conveyed by the air in atomised form into the recess is for combustion therein. Fur thermore, since the fuel is withdrawn by induction from chamber 5 the non-return valve 2i is enabled to open against the action of its return spring ill for replenishment of the chamber 8 by way of feed ducts t from a fuel supply line connected to said duct, under the control of a needle valve serving in the manner above described as a fuel metering device.

If desired, the peripheral surface of the body 3 may '33, and/or the upper part of the wall of aperture it may be made convex to impart to the annular passage til a Venturi form in radial section.

The embodiments above described with reference to the drawings are merely examples of various modes in which the invention may be practiced and it will be appreciated that variations may be made in the fuel atomising means in relation to cylinder heads and pistons having other forms, without exceeding the scope of the invention.

For example, the cylinder head may have a recess and include or support adjacent thereto atomising means comprising a fuel receiving chamber, for example a toric chamber, at least one atoinising bore extending for example upwardly and inwardly to the recess, and the obturator body may be provided on the piston crown to enter the recess in the cylinder head so as to divide the combustion chamber into two volumes, one enclosed in the recess by said body. and the other enclosed between the remaining surfaces of the cylinder head and the piston crown and having a higher rate of volume reduction so as to create the aforesaid air squish be made convex at the zone of the bores effect. In such an arrangement, various dispositions of atomising ducts and air passages may be embodied. One such disposition may correspond, for example, to the means illustrated in Figures 1 and 2 of the drawings, wherein fuel is expelled from the receiving chamber into the recess by the air squish effect. Another such disposition may correspond, for ezlample, to the means illustrated wherein fuel is withdrawn from the receiving chamber by inductive action of the air under displacement, either in a manner similar to that described with reference to Figure 3 by he provision of passages through the material of the cylinder across the ends of atomising bores, or in a manner similar to that described with reference to Figure a by the disposition of the atoniising cores to open into the peripheral wall of an aperture in the cylinder head from the recess therein, so that fuel in said bores is disposed for induction by air under displacement in the annular passage between the periphery of the obturator on the piston and the wall of said aperture.

I claim:

In a compression ignition internal combustion engine having a cylindrical head element and a piston crown element which cooperate to form a combustion chamber, and wherein the piston crown. element is formed with a recess adapted to receive injected atomized fuel, fuel atomizing means comprising, in combination, an obturator body secured to the cylinder head and projecting into the combustion chamber so as to enter and substantially enclose said recess on the approach of the piston crown element to the cylinder head element whereby the combustion chamber is divided into two volumes, one of said volumes comprising recess and being subject to a lower rate of volume reduction than the other of said volumes, said obturator body being formed with receiving chamber for fuel, with a feed duct to said receiving chamber, and with an axial passage communicating with said receiving chamber and ending in a frusto-conical Valve seat located at the inner end of said obturator body, said obturator body being also formed with a. transverse passage connecting said receiving chamber with the other of said volumes of said combustion chamber for the passing of displaced air from said other volume through said receiving chamber to said one volume; a non return valve located in said feed duct of said obturator body; a frusto-conical valve cooperating with said frusto-conical valve seat; and resilient means urging said frusto-conical valve into engagement with said valve seat, said :frusto-conical valve being adapted to be raised from said valve seat by displaced air passing through said axial passage to said one volume.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,648,647 Krettingen Nov. 8, 1927 1,872,761 Leonard Aug. 23, 1932 1,943,495 Thomas Jan. 16, 1934 2,022,574 Witkowski Mar. 2, 1937 2,151,218 Lutz Mar. 21, 1939 2,171,912 Boxan Sept. 5, 1939 2,488,857 Firing Nov. 22, 1949 FOREIGN PATENTS Number Country Date 231,884 Great Britain Sept. 10, 1925 489,782 Germany Jan. 22, 1930 

